Detection of unknown primary neuroendocrine tumors (CUP-NET) using 68Ga DOTA-NOC receptor PET/CT

4599 Background: This bi-centric study aimed at determining the role of receptor PET/CT using 68Ga-DOTA-NOC in the detection of undiagnosed primary sites of neuroendocrine tumours (NETs). Methods: Overall 59 patients (M: F 33:26, age 65±9 yr) with documented NET and unknown primary, were enrolled. PET/CT was performed after injection of approximately 100 MBq (46–260 MBq) of 68Ga-DOTA-NOC. The maximum standardised uptake values (SUVmax) were calculated and compared with SUVmax in known pancreatic NET (pNET) and ileum / jejunum / duodenum (SI-NET). The results of PET/CT were also correlated with CT alone. Results: In 35/59 (59%) of patients, 68Ga-DOTA-NOC PET/CT localised the site of the primary: ileum/jejunum (14), pancreas (16), rectum (2), lungs (2) and paraganglioma (1). CT alone (on retrospective analyses) confirmed the findings in 12/59 (20%) patients. The mean SUVmax of identified previously unknown pNET and SI-Net were 18.6 ± 9.8 (range 7.8–34.8) and 9.1± 6.0 (range 4.2–27.8), respectively. SUVmax i...